This invention relates to biometric authentication devices and, more particularly, to apparatus and methods for culling substantially redundant data in fingerprint sensing circuits.
Fingerprint recognition and authentication systems are well recognized and highly reputed as reliable, non-intrusive ways to verify individual identity. Historically, however, the size and cost of fingerprint sensors needed to implement fingerprint recognition and authentication technology have limited their widespread use. Indeed, many conventional fingerprint recognition technologies often utilize large fingerprint sensing components (e.g., integrated circuits), rendering them impracticable and often cost-prohibitive for many portable or small applications, such as personal digital assistants, peripheral computer components, or cell phones.
Recent developments in fingerprint recognition and authentication systems have focused on “swipe”-type fingerprint sensors that significantly reduce the real estate needed to digitally capture and verify fingerprints. Particularly, such sensors provide a small-area sensor element that repeatedly scans portions (e.g., lines) of a fingerprint as it is swiped over the sensor. Later, the portions may be reconstructed to provide a complete fingerprint image for recognition and authentication purposes.
In many “swipe”-type fingerprint sensors, data acquired from the fingerprint sensor must be transmitted to a host system to enable image reconstruction and fingerprint image recognition and authentication. Often, redundant information is unnecessarily transmitted, stored, and processed by the host system as a result of time-dependent sampling that fails to account for slower swipe speeds or a lack of motion across the sensor. The redundant information and resources needed to process the redundant information unnecessarily and undesirably consumes large amounts of bandwidth, memory, and power in both the fingerprint sensing circuit and the host system.
In view of the foregoing, what is needed is an apparatus and method for reducing the amount of redundant data that is generated by “swipe”-type fingerprint sensors and transmitted to host fingerprint recognition and authentication systems. Ideally, such an apparatus and method would reduce the amount of energy, bandwidth, and memory that is required to transmit and store fingerprint data. Further needed are apparatus and methods for efficiently detecting motion across “swipe”-type fingerprint sensors. As will become evident herein, apparatus and methods in accordance with the invention satisfy many, if not all, of the above-stated needs.